docker: add unsloth-studio-update for in-place Studio updates

Updating Studio in the container previously meant pulling a fresh ~25GB image
(or at best the ~6GB fused Studio layer) for what is usually a small Python/UI
change. Add a baked helper so a running container can update in place:

    docker exec <container> unsloth-studio-update

It updates only the Studio packages -- the backend code and the pre-built
frontend, which ships inside the unsloth wheel -- with `pip install -U
--no-deps unsloth unsloth_zoo`, then restarts just the studio service via
supervisor. The torch/CUDA stack is left untouched, so it is safe in both GPU
and CPU-only containers. This deliberately avoids `unsloth studio update`,
which re-runs the full installer and re-probes the GPU to pick torch wheels --
in a container started without --gpus that finds no GPU and can downgrade torch
to CPU/cu126.

Options: --ref <branch|tag|sha> installs from git (track main) instead of the
latest PyPI release; --with-deps also updates dependencies; --no-restart defers
the restart. After the swap the helper smoke-imports studio.backend.main and,
if a transitive dep is now missing, points the user at --with-deps.

The update lands in the container's writable layer (survives docker restart);
mount -v unsloth_studio_home:/opt/unsloth-studio to keep it across a recreate.

docker/.dockerignore

@@ -5,6 +5,7 @@
 !fetch_llama_prebuilt.py
 !supervisord.conf
 !studio_launch.sh
+!unsloth_studio_update.sh
 !unsloth_nb_compat.py
 !unsloth_pip_shim.py
 !unsloth_ipython_startup.py

docker/Dockerfile.studio

@@ -156,7 +156,11 @@ RUN set -eux \
 
 COPY supervisord.conf /etc/supervisor/supervisord.conf
 COPY studio_launch.sh /usr/local/bin/unsloth-studio-launch
-RUN chmod +x /usr/local/bin/unsloth-studio-launch
+# In-place Studio updater: `docker exec <container> unsloth-studio-update`
+# refreshes the Studio packages (backend + baked frontend) and restarts the
+# service, without pulling a new image or touching the torch/CUDA stack.
+COPY unsloth_studio_update.sh /usr/local/bin/unsloth-studio-update
+RUN chmod +x /usr/local/bin/unsloth-studio-launch /usr/local/bin/unsloth-studio-update
 
 # Studio web UI, JupyterLab, sshd. All bind 0.0.0.0 inside the container's
 # network namespace; the operator publishes them explicitly with -p.

docker/unsloth_studio_update.sh

@@ -0,0 +1,101 @@
+#!/usr/bin/env bash
+# Update Unsloth Studio in place, inside a running container, without pulling a
+# new image. Updates ONLY the Studio Python packages (the backend code and the
+# pre-built frontend, which ships inside the unsloth wheel) and restarts the
+# Studio service. The torch/CUDA stack is left untouched.
+#
+#   docker exec <container> unsloth-studio-update              # latest PyPI release
+#   docker exec <container> unsloth-studio-update --ref main   # latest git main
+#   docker exec <container> unsloth-studio-update --with-deps  # also update deps
+#   docker exec <container> unsloth-studio-update --no-restart # update, restart later
+#
+# Why not `unsloth studio update`: that command re-runs the full installer,
+# which re-probes the host GPU to pick torch wheels. In a CPU-only container
+# (run without --gpus) it finds no GPU and can downgrade torch to CPU/cu126,
+# breaking CUDA. This helper only touches the Studio packages, so it is safe in
+# both GPU and CPU containers.
+#
+# Persistence: the update is written to the container's writable layer, so it
+# survives `docker restart`. To keep it across a full `docker rm` + `docker run`
+# (and to keep your chats/users/models), run Studio with its home on a named
+# volume: -v unsloth_studio_home:/opt/unsloth-studio
+set -euo pipefail
+
+STUDIO_HOME="${UNSLOTH_STUDIO_HOME:-/opt/unsloth-studio}"
+REF=""
+NO_DEPS="--no-deps"
+RESTART=1
+PACKAGES="unsloth unsloth_zoo"
+
+usage() { sed -n '2,21p' "$0"; }
+
+while [ $# -gt 0 ]; do
+    case "$1" in
+        --ref)         REF="$2"; shift 2;;
+        --with-deps)   NO_DEPS=""; shift;;
+        --no-restart)  RESTART=0; shift;;
+        --packages)    PACKAGES="$2"; shift 2;;
+        -h|--help)     usage; exit 0;;
+        *) echo "unsloth-studio-update: unknown argument: $1" >&2; usage; exit 2;;
+    esac
+done
+
+# Resolve the Studio venv python. Prefer the venv directly; fall back to
+# following the launcher symlink ($STUDIO_HOME/bin/unsloth -> venv/bin/unsloth).
+PY=""
+for cand in \
+    "$STUDIO_HOME/unsloth_studio/bin/python" \
+    "$STUDIO_HOME/unsloth_studio/bin/python3"; do
+    [ -x "$cand" ] && { PY="$cand"; break; }
+done
+if [ -z "$PY" ] && [ -L "$STUDIO_HOME/bin/unsloth" ]; then
+    venv_bin="$(dirname "$(readlink -f "$STUDIO_HOME/bin/unsloth")")"
+    [ -x "$venv_bin/python" ] && PY="$venv_bin/python"
+fi
+[ -n "$PY" ] || { echo "unsloth-studio-update: could not find the Studio venv under $STUDIO_HOME" >&2; exit 1; }
+
+version_of() { "$PY" -c "from importlib.metadata import version; print(version('unsloth'))" 2>/dev/null || echo "unknown"; }
+
+echo "[studio-update] Studio venv: $PY"
+echo "[studio-update] before: unsloth $(version_of)"
+
+# Build the package specs. With --ref, install from git so you can track main
+# (or any branch/tag/sha); otherwise take the latest PyPI release.
+if [ -n "$REF" ]; then
+    SPECS="git+https://github.com/unslothai/unsloth.git@${REF}#egg=unsloth"
+    SPECS="$SPECS git+https://github.com/unslothai/unsloth-zoo.git@${REF}#egg=unsloth_zoo"
+    echo "[studio-update] installing from git @${REF}"
+else
+    SPECS="$PACKAGES"
+    echo "[studio-update] installing latest release of: $PACKAGES"
+fi
+
+# shellcheck disable=SC2086
+"$PY" -m pip install -U $NO_DEPS $SPECS
+
+echo "[studio-update] after:  unsloth $(version_of)"
+
+# Sanity: the backend must still import after the swap (a missing transitive
+# dep from --no-deps shows up here). Non-fatal: just warn with the remedy.
+if ! "$PY" -c "import studio.backend.main" >/dev/null 2>&1; then
+    echo "[studio-update] WARNING: 'import studio.backend.main' failed after update." >&2
+    echo "[studio-update] A new dependency may be missing. Re-run with --with-deps:" >&2
+    echo "[studio-update]   unsloth-studio-update --with-deps" >&2
+fi
+
+if [ "$RESTART" = "1" ]; then
+    SUPCTL="$(command -v supervisorctl || true)"
+    [ -n "$SUPCTL" ] || SUPCTL="/opt/unsloth-venv/bin/supervisorctl"
+    if [ -x "$SUPCTL" ] && "$SUPCTL" status studio >/dev/null 2>&1; then
+        echo "[studio-update] restarting the studio service"
+        "$SUPCTL" restart studio
+    else
+        echo "[studio-update] supervisor not managing 'studio' here; restart Studio yourself"
+        echo "[studio-update]   (e.g. 'docker restart <container>')"
+    fi
+else
+    echo "[studio-update] --no-restart: restart Studio to load the update"
+    echo "[studio-update]   docker exec <container> supervisorctl restart studio"
+fi
+
+echo "[studio-update] done"